JPS6199303A - Oxide voltage non-linear resistor - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a voltage nonlinear resistor (hereinafter referred to as a varistor) used for absorbing abnormally high voltage in an electric circuit.

[Conventional technology]

As an oxide varistor containing ZnO as a main component, a varistor made by adding Biass, Coo, MnO, Ti1t, BaO, and N1Fz to ZnO is known, for example, from Japanese Patent Publication No. 53-21510. Also, Zn
Varistor made by adding BaO1Coo to O (Special Publications Showa 4)
8-6755) is also known.

[Problem that the invention seeks to solve]

However, in the former varistor, the varistor voltage V1 is about 5~
Suitable for the 80v range, but not suitable for high voltages above about 80v. In addition, nonlinearity in the large current region is bad (,
It also has the disadvantage that the varistor voltage changes greatly in response to surges. On the other hand, the latter varistor has a non-linearity index of about 1O to 20, and in order to make the non-linearity index about 3O, it is necessary to apply Coo to a sintered body made by adding BaO to ZnO and firing it again. It has the disadvantage that it has to be done. These oxide varistors doped with BaO are essentially unsuitable for high voltage and large current applications.

The recent development of electronic equipment is remarkable, and in particular, many semiconductor elements are used, so strong absorption of abnormal voltage and voltage stabilization are required.For this purpose, K makes it easy to control the varistor voltage. A varistor is required that has a large non-linearity index α and stable characteristics against loads.An object of the present invention is therefore to provide a varistor that can satisfy these requirements. .

[Means for solving problems]

The varistor of the present invention for achieving the above object is made of Zn
(zinc), Ba (barium), sb (antimony)
, Co (cobalt), B (boron), Al (aluminum), and their typical oxides such as Zn0 (zinc oxide), Bad (barium oxide), 5btOsC (antimony oxide), Coo (antimony oxide), Composition calculated as cobalt), Btus (boron oxide), AbOs (aluminum oxide), Zn063-95 to 98.699%
k%, Ba0O・1~3%/L/%, Sb20
+ O-1~5-E: j&%, Cool'~
25 mol%, Bt Os O-1 to 3 mol%, Al
It consists of a sintered body containing 20 so, ooi to 0.05 mol%.

[For production]

According to the above invention, due to the synergistic effect of each component, it is possible to obtain a varistor that can easily control the varistor voltage, has a large nonlinear index, and has stable characteristics against loads.

〔Example〕

Next, embodiments of the present invention will be described with reference to the drawings.
In order to manufacture the oxide varistor of the present invention, first, ZnO is 63.95 to 98.699 mol%, BaO is 0.1 to 98.699 mol%.
3 MoA/%, 5b20s is O-1~5% Le%, C
oO is 1~25%/I/%, Btus is 0.1~
3% to %, A1. O.

is 0. '001 to 0.05 mol%, and each oxide raw material is calculated so that the total of these is 100 mol%, and after thoroughly mixing this with a ball mill etc., an organic binder such as methylcellulose aqueous solution is added. It was granulated using. In addition, as a starting material, it is also possible to use a hydroxide, a carbonate, a binary metal oxide, etc. instead of an oxide. In addition, if it causes problems such as variations in dimensions and properties after molding and firing, calcining in 600 to 1000 tons of air for 1 to 3 hours, pulverizing this into a fine powder, and then granulating it. good. The granulated powders of various compositions obtained in this way are press-molded at a pressure of 1 to 3 ton/cm2, and finished into a disc shape with a diameter of 15 mm and a length of 1 mm.
Further, this molded product is fired for 1 to 3 hours in air of 1000 to 14001:', and finally, Ag is applied to both sides of this sintered body.
Electrodes are formed by applying a paste and baking it.
We have completed oxide varistor elements with various compositions.

FIG. 1 is a sectional view showing the principle of an oxide varistor manufactured by the method described above. It is thought that the varistor action of this oxide varistor is caused by the conductive microcrystals (1) and the high resistance layer (2) surrounding them. Therefore, by changing the material composition and firing conditions, the varistor voltage and nonlinear index can be controlled. As mentioned in 5 above, since the varistor action occurs inside the sintered body, there are no particular limitations on the material or forming method of the electrode (3), and Ag, In,
Similar results can be obtained with electrodes formed by vapor deposition of Al, Sn, etc., or electrodes formed by Ni plating.

When we measured the varistor voltage (■) of various varistors manufactured by the above-mentioned method, the voltage ratio R indicating voltage nonlinearity, and the voltage change rate Δ■1 indicating one-voltage resistance, the results are shown in Figures 2- The results shown in FIG. 6 were obtained. In the graphs of FIGS. 2 to 6, the Vo and R1Δv1 values of typical compositions are marked with 1, fish eggs, circles, and triangles. Further, in each drawing, for comparison, characteristics of varistors having compositions outside the scope of the present invention are also shown as comparative examples. Also,
The amount (mol %) of each component on the horizontal axis of FIGS. 2 to 6 is shown on a logarithmic scale. Further, the varistor voltage v1 is 1.0. It was determined from K by measuring the terminal voltage when mA was applied. Voltage ratio R is varistor current 1
．． Varistor terminal voltage Vt and v at 0mA and 25A
, o and calculated Visa/V+. Therefore, the smaller the voltage ratio R is, the better the voltage ratio linearity is, and the larger the non-linearity index α is. Voltage change 1 rate Δv
1c, 8x20μs waveform Te1250Al')? −
This was determined by passing a current through the varistor twice, measuring the varistor voltage v1 in the opposite direction before and after the current was passed, and calculating the amount of change. Therefore, the voltage change rate ΔVt
The smaller the (absolute value), the better the surge resistance and the better the stability against load.

Next, FIGS. 2 to 6 will be explained in more detail.

FIG. 2 shows the varistor voltage v1, voltage ratio R, and voltage change rate ΔV of a varistor having the following composition.

ZnO80,49-85.44 mol%BaOo,o
s ~5 mol% sb, o, 2.0 molsi constant C
oo 12.0 Morsi Constant B Tomi O8
0. S Morsi constant 1,0. 0.01 mol 5 fixed total 100 mol, that is, Figure 2 is B
Vs and R1 of various varistors in which the amount of aO (mol%) and the amount of ZnO were changed so that the total amount was 100 mol%
ΔV1 is shown. In addition, in Figures 2 to 6, ZnO
The amount is inevitably determined once the mole percent of the component on the horizontal axis in each figure is determined.

FIG. 3 shows the varistor voltage vl, voltage ratio R, and voltage change rate Δv1 of a varistor having the following composition.

ZnO76,99~86.94-e y%5btOs
0.05 to 10 mol% BaOO, 5 molsi constant Coo 12.0 molsi constant B!
os O, 5 Morsi constant Altos
0-01 mole 5 fixed total
100 mol%, that is, Figure 3 shows the amount of 5btos (Mo/I/%) and Z
V, , R, △V of various varistors with varying amounts of nO
Indicates I.

FIG. 4 shows the varistor voltage V of a varistor with the following composition.

, voltage ratio R, and voltage change rate ΔV.

ZnO66,99~96.49 4#%Coo
0.5 to 30 mol% BaOQ・5 Morsi constant sb, o, 2.0 Morsi constant Bt
Os 0, 5 Morsi constant Al2
0s O・Ol Morsi constant total
100 mol% That is, in FIG. 4, the amount of CoO (mol%) and the amount of It ZnO were varied so that the total amount was 100 mol%,
The V, , R, and ΔV of various varistors are shown.

FIG. 5 shows the varistor voltage V of a varistor with the following composition.

, voltage ratio R, and voltage change rate Δv1.

ZnO75.49-85.44 mol%BzOs
0-05 to 10 mol%Ba0
0,5 Morsi constant 5btOs
2-0 Morsi constant CoO 1
2.0 Morsi constant AbOs 0-
01 MoSb2O30.1～-C Total 1
00 mol %, Figure 5 shows the Vt, R, Δv1 of various varistors with varying amounts of B2O3 (mol %) and ZnO to give a total of 100 mol %.

FIG. 6 shows the varistor voltage V1, voltage ratio R, and voltage change rate ΔV of a varistor having the following composition.

Zn0 84.9 ~ 84-9995 mol% Al
tos 0-0005~O-1 mol%BaO0.5
Mo/I/% constant 5bzO52-0 Morsi constant Coo 12.0 Morsi constant Bt
Os O-5 molsisi total
100 mol%, that is, FIG.
amount (mol%) and Z so that the total is 100 moA/%
V, , R1Δv of various varistors with varying amounts of nO
Indicates l.

Next, the reason for limiting the material composition in the present invention will be explained.

In FIG. 2, when BaO exceeds 3.0 mol %, the voltage change rate ΔVl is large. On the other hand, those containing less than 0.1 mol % of BaO have a large voltage change rate and a large voltage ratio R. Therefore, in order to obtain a varistor with a small voltage ratio R and stable resistance to load, the preferred range of BaO is 0.1 to
The amount is 3.0 mol%, and the more preferable range is 0.2 to 1 mol%.

In FIG. 3, when 5b20s exceeds 5.0 mol%, the voltage change rate ΔV+ is large. On the other hand, 5btOs
Even if it is less than 10.1 mol %, the voltage change rate is large and the voltage ratio R is also large. Therefore, in order to obtain a varistor with a small voltage ratio R and stable against loads, the preferable range of Sb*Os is 0.1 to 5.0 mol%, and the more preferable range is 0.5 to 2 mol%. /%.

In FIG. 4, when Coo exceeds 25.0 mol%, the voltage change rate Δ■1 is large. On the other hand, Coo is 1.0
If it is less than mol %, the voltage change rate ΔV is large and the voltage ratio R is also large. Therefore, in order to obtain a varistor with a small voltage ratio R and stable against loads, the preferable range of Coo is 1.0 to 25.0 mol%, and the more preferable range is 5 to 20 mol%.

In FIG. 5, B20. If it exceeds 3.0 mol%, the voltage change rate Δ■1 is large. On the other hand, B, Os is 0
．． Even when the amount is less than 1 mol %, the voltage change rate ΔV1 is large.

Therefore, in order to obtain a varistor with a small voltage ratio R and stable against loads, the preferable range of B2O3 is 0.1 to 3.
0 mol%, and a more preferable range is 0.3 to 1 mol%
It is.

In FIG. 6, when Altos exceeds 0.05 mol %, the voltage change rate Δ■1 is large and the voltage ratio R is also large.

On the other hand, those containing less than 0.001 mol % of Altos also have a large voltage change rate. Therefore, the voltage ratio R is small and the load is stable (to obtain the risk)
The preferred range of tOs is 0.001 to 0.05 mol%, and the more preferred range is 0.003 to 0.02 mol%.
It is mole%.

Note that the range of zn is the remainder, which necessarily ranges from 63.95 to
It becomes 98.699 mol%.

Although Examples and Comparative Examples of the present invention have been described above, the present invention is not limited thereto and can be further modified. For example, rare earth substances (La2O5, PrtOs, NdtOs, etc.), Nbt05, TaxOs, Mn0. Ni01
Oxides such as Cr203 may be added.

〔Effect of the invention〕

As is clear from the above, according to the present invention, it is possible to provide a varistor in which the risk voltage v1 is 50 or more, the voltage ratio R is 2.5 or less, and the voltage change rate Δv1 is within ±10%. That is, The voltage ratio is small and has excellent stability against surges (can provide risks).

[Brief explanation of the drawing]

FIG. 1 is a cross-sectional view schematically showing the arrangement of sintered crystal grains of an oxide voltage nonlinear resistor according to the present invention, and FIG. 2 is a cross-sectional view of a BaO
A characteristic curve diagram showing changes in varistor voltage Vl and voltage change rate Δv1 with respect to changes in voltage ratio R1, Fig. 3 is 5bzOs
Figure 4 is a characteristic curve diagram showing changes in varistor voltage v1 and voltage ratio R1 voltage change rate Δ■1 with respect to changes in CoO.
■Characteristic curve diagram showing changes in , Figure 5 shows varistor voltage ■8 and voltage ratio R1 voltage change rate Δ■ with respect to changes in B2O3
Figure 6 shows the varistor voltage v1 and voltage ratio R1 voltage change rate Δv for changes in Al and 03.
FIG. 3 is a characteristic curve diagram showing changes in l. (1)...Crystal, (2)...High resistance layer, (3)...
·electrode.

Claims (1)

[Claims] (1) Zn, Ba, Sb, Co, B, and Al are combined with their typical oxides ZnO, BaO, Sb_2O_
3. Composition converted to CoO, B_2O_3 and Al_2O_3: ZnO 63.95-98.699 mol% BaO 0.1-3 mol% Sb_2O_3 0.1-5 mol% CoO 1-25 mol% B_2O_3 0.1- An oxide voltage nonlinear resistor comprising a sintered body containing 3 mol% Al_2O_3 0.001 to 0.05 mol%.